Apolipoprotein E regulates primary cultured human mesangial cell proliferation

Area of Science:

• Nephrology
• Cell Biology
• Lipid Metabolism

Background:

• The specific role of apolipoprotein E (apo E) in kidney disease remains largely undetermined.
• Previous animal studies yielded results of questionable relevance to human physiology.
• This study investigates apo E's function in human kidneys using primary cultured normal human mesangial cells (NHMCs).

Purpose of the Study:

• To elucidate the effects of apo E on normal human mesangial cells (NHMCs).
• To determine the impact of different apo E isoforms (E2, E3, E4) on NHMC behavior.
• To assess the combined effects of apo E and apo B on NHMC proliferation.

Main Methods:

• NHMCs were co-cultured with apo E (including isoforms E2, E3, E4) and/or apo B in serum-free medium.
• Cell proliferation was quantified using the Premix WST-1 Cell Proliferation Assay System.
• Apoptosis was assessed using the DNA-Prep Reagent System.

Main Results:

• Apo E initially increased NHMC proliferation at 24 hours but inhibited it after 48 hours.
• Concentration-dependent inhibition of NHMC proliferation by apo E was observed at 72 hours (>0.78 microg/ml).
• Co-culture with both apo E and apo B resulted in intermediate NHMC proliferation levels compared to either alone. Apo E isoforms differentially inhibited proliferation, and neither apo E nor apo B induced apoptosis.

Conclusions:

• Apolipoprotein E modulates NHMC proliferation, exhibiting a potential protective effect on the kidney by inhibiting proliferation and reducing apo B-induced proliferation.
• Apo E can also increase proliferation under specific experimental conditions.
• These findings suggest a complex regulatory role for apo E in human kidney cell function.